UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

MEMORANDUM 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

PC Code: 080803 

DP: 409990, 410271 

Date: May 13, 2013 

SUBJECT: Review of Atrazine Ecological Monitoring Program - Proposal for 2013, dated 

March 8, 2013; submitted by Syngenta Crop Protection, LLC. 

TO: Monica Wait, Chemical Review Manager 

Patricia Parrott, Chief 

Risk Management and Implementation Branch III 

Pesticide Re-Evaluation Division 

FROM: l Frank T. Farruggia, Ph:D., Biologist 

James Hetrick, Ph.D., Senior Science Advisor 

Environmental Risk Branch III 

Envirorunental Fate ~i 

THROUGH: Dana 

Rosanna 

Spatz, 

Louie-Juzwiak, 

Chief 

RAPL 

~ 

Environmental Risk Branch III 

Environmental Fate and Effects Division 

In a proposal for conducting the Atrazine Ecological Monitoring Program (AEMP) in 2013, 

Syngenta has requested to decommission 20 com/sorghum monitoring sites and the remaining 

two sugarcane sites. Syngenta proposes to continue monitoring at nine watershed sites. 

The 20 com/sorghum sites in the request include: IA-03, IL-101

, IL-12, IL-14, IL-15, IL-16, IL17, IN-12, KS-01, KS-02, KS-03, M0-04A, M0-05, M0-05B, M0-06, NE-05, NE-09, OH-05\ 

OH-06 and TX-02. The two sugarcane sites included in the decommissioning request are LA-01 

and LA-03. 

1 This site was considered acceptable for decommissioning in 2012; however, the registrant continued to monitor to 

evaluate their ongoing projects in the watershed. 

' 
2

After reviewing the results of the monitoring data from the AEMP and the registrant’s rationale 

for the decommissioning requests, EFED can concur with decommissioning all of the proposed 

sites listed above. The vulnerability of these sites to atrazine runoff is well understood, and the 

60-day running average atrazine concentrations in these watersheds are below the current level 

of concern (LOC) of 10-ppb atrazine over a 60-day period 

(http://www.epa.gov/pesticides/reregistration/atrazine/atrazine_update.htm#post-red). 

The 60-day running average atrazine concentrations in the IA-04, IA-05, LA-04, MO-07, MO08, and TX-01 watersheds have been above the atrazine LOC for at least two of the last three 

years (Table 1), and thus concerns remain regarding the health of the aquatic plant communities 

in these watersheds. Thus, in addition to MO-1, MO-2 and NE-04, where Syngenta has focused 

their stewardship efforts, IA-04, IA-05, LA-04, MO-07, MO-08, and TX-01 will continue to be 

monitored as part of the AEMP in 2013. 

As for the remaining two sugarcane sites in the AEMP, EFED can concur with the 

decommissioning request, as recent monitoring results have shown atrazine concentrations below 

levels of concern (Table 2). 

Table 1. Summary of atrazine concentrations in corn/sorghum 

AEMP sites from the past 3 years. Sites decommissioned in 2012 

are indicated with “NA”. Bolded values indicate an LOC 

exceedance. 

Site ID Max 60‐day Avg Value (μg/L)

2010 2011 2012

IA‐03 10.5 4.9 2.0

IA‐04 10.4 4.3 10.9

IA‐05 11.3 12.8 7.0

IL‐10 0.4 1.4 0.7

IL‐11 1.1 1.8 NA

IL‐12 6.9 4.6 5.6

IL‐13 0.7 1.4 NA

IL‐14 5.2 4.9 3.4

IL‐15 6.8 6.8 7.0

IL‐16 7.5 2.6 9.5

IL‐17 5.7 17.2 6.3

IN‐12 4.5 4.2 1.5

KS‐01 5.4 1.5 2.6

KS‐02 8.9 3.5 1.6

KS‐03 11.6 5.9 4.4

LA‐04 6.3 27.4 11.5

LA‐05 3.3 4.2 NA

MO‐01 5.1 4.5 1.4
3

MO‐02 8.4 6.6 1.8

MO‐04A 8.7 11.5 7.5

MO‐05 12.9 6.2 4.0

MO‐05B 12.3 8.3 5.6

MO‐06 6.3 6.9 3.7

MO‐07 20.2 14.6 11.9

MO‐08 14.5 14.1 11.2

NE‐04 34.7 3.4 2.4

NE‐05 8.1 2.3 1.0

NE‐09 6.2 1.2 4.9

OH‐05 2.0 1.4 1.9

OH‐06 3.8 5.9 5.2

TX‐01 13.5 3.0 15.6

TX‐02 3.7 0.2 3.3

Table 2. Summary of atrazine concentrations in the remaining 

active Louisiana sugarcane AEMP sites from 2005-2012. Bolded 

values indicate an LOC exceedance. 

Site ID Year

Max 60‐day Avg

Value (μg/L)

LA‐01

2005 7.6

2006 2.3

2007 12.7

2008 8.1

2009 10.0

2010 9.5

2011 5.3

2012 2.2

LA‐03

2005 14.3

2006 3.7

2007 3.0

2008 6.3

2009 2.1

2010 0.6

2011 0.8

2012 0.6